SCANGREEN 2015-18: Turfgrass species, varieties, seed mixtures and seed blends for Scandinavian putting greens. Final results from a four year testing period

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Trygve S. Aamlid¹, Pia Heltoft¹, Gudni Thorvaldsson², Anne Mette Dahl Jensen³, Tatsiana Espevig¹, Karin Juul Hesselsøe¹, Wendy Waalen¹, Torben Kastrup Petersen⁴, Trond Pettersen¹, Jan Tangsveen¹, Per Sørensen⁵, Tania Gneist⁵ and Bjarni Hannesson⁶

NIBIO REPORT | VOL. 5 | NO. 154 | 2019

SCANGREEN 2015‐18:

Turfgrass species, varieties, seed mixtures and seed blends for Scandinavian putting greens

Final results from a four year testing period

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TITTEL/TITLE

SCANGREEN 2015-18: Turfgrass species, varieties, seed mixtures and seed blends for Scandinavian putting greens. Final results from a four year testing period

FORFATTER(E)/AUTHOR(S)

Trygve S. Aamlid, Pia Heltoft, Gudni Thorvaldsson, Anne Mette Dahl Jensen, Tatsiana Espevig, Karin Juul Hesselsøe, Wendy Waalen, Torben Kastrup Petersen, Trond Pettersen, Jan Tangsveen, Per Sørensen, Tania Gneist and Bjarni Hannesson

DATO/DATE:

08.01.2021

REPORT NO. /:RAPPORT NR.

5/154/2019

TILGJENGELIGHET/AVAILABILITY:

Åpen/ Open

PROSJEKTNR./PROJECT NO.:

8894

SAKSNR./ARCHIVE NO.:

19/00686

ISBN:

978-82-17-02454-5

ISSN:

2464-1162

ANTALL SIDER/NO. OF PAGES:

94

NO. OF APPENDICES / ANTALL VEDLEGG/

1

EMPLOYER / OPPDRAGSGIVER

STERF (Scandinavian Turfgrass and Environment Research Foundation)

CONTACT PERSON / KONTAKTPERSON

Maria Strandberg

KEYWORDS / STIKKORD : FIELD OF WORK / FAGOMRÅDE

English: Golf, green, seed, seed blends, seed mixtures, turfgrass variety evaluation

Urban greening and vegetation ecology

Norsk: Golf, greener, frø, frøblandinger, gras til grøntanlegg, sortsprøving

Grøntanlegg og vegetasjonsøkologi

SUMMARY / SAMMENDRAG :

This is the final report from the STERF project: SCANGREEN 2015-18 Denne tekst er sluttrapport for STERF-prosjektet: SCANGREEN 2015-18

GODKJENT /APPROVED

HÅKON BORCH

PROSJEKTLEDER /PROJECT LEADER

TRYGVE S. AAMLID

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Preface

For variety testing to be relevant to the end users it is critical that the trials are conducted under realistic conditions with regard to mowing height, wear, fertilization and other management practices.

The SCANGREEN program was initiated in 2003 and involves testing of turfgrass species and varieties on sand-based golf greens at four sites in the Nordic countries. The evaluation is organized in four- year testing cycles and forms the basis for recommended variety lists at www.scanturf.org and www.sterf.org.

The present report gives a detailed account of methods and results obtained during the fourth

SCANGREEN test cycle from 2015 to 2018. Unlike previous cycles, this evaluation also included seed blends and -mixtures of special relevance to the golf industry in the Nordic countries.

As with the earlier test cycles, SCANGREEN 2015-18 was funded 10% by fees paid by the seed

companies entering varieties into the trials, and 90% by the Scandinavian Turfgrass and Environment Research Foundation (STERF). Thanks are expressed to both parties for funding and excellent

collaboration during the course of the project.

NIBIO Landvik, 08.01.21

Trygve S. Aamlid Project leader

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Content

1 Introduction ... 7

2 Materials and methods ... 8

2.1 Pure species and varieties entered by plant breeders / seed companies into the project ... 8

2.2 Seed blends and mixtures added to the trials ... 9

2.3 Experimental sites and protocol ... 10

2.4 Weather conditions and implementation of protocol ... 11

2.4.1 Establishment and maintenance of the trials in 2015... 13

2.4.2 Winter 2015‐16 and management in 2016 ... 17

2.5 Assessments, statistical analyses and presentation of results ... 30

3 Results and discussion ... 31

3.1 Comparison of pure species (Table 10) ... 31

3.1.1 Agrostis stolonifera ... 31

3.1.2 Agrostis capillaris ... 31

3.1.3 Agrostis canina ... 31

3.1.4 Festuca rubra ssp. commutata ... 31

3.1.5 Festuca rubra ssp. litoralis ... 31

3.1.6 Lolium perenne ... 31

3.1.7 Poa trivialis ... 31

3.1.8 Poa annua ... 32

3.1.9 Poa pratensis ... 32

3.2 Varieties of Festuca rubra ssp. commutata (Table 11) ... 40

3.3 Varieties of Festuca rubra ssp. litoralis (Table 12) ... 40

3.4 Varieties of Agrostis capillaris (Table 13) ... 49

3.5 Varieties of Agrostis stolonifera (Table 14) ... 55

3.6 Varieties of Lolium perenne (Table 15) ... 64

3.7 Varieties of Poa trivialis (Table 16) ... 69

3.8 Seed blends of Festuca rubra subspecies (Table 17) ... 74

3.9 Poa annua, Poa trivialis or Lolium perenne as nurse grasses for A. stolonifera (Table 18) ... 74

3.10Seed mixtures of Festuca and Agrostis (Table 19) ... 84

References ... 94

Appendix 1: Protocol for Scangreen 2015‐18 ... 95

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Abstract

Knowledge about and optimal choice of seed of the many new turfgrass varieties coming to the market is important for sustainable turfgrass management. The objective of SCANGREEN 2015-18 was to find species, varieties and seed blends/mixtures of Agrostis, Festuca, Poa and Lolium that are suited for pesticide-free management of putting greens in the two major climatic zones of the Nordic countries.

The four test sites were Reykjavik GC, Iceland (64.1°N, 21.9°W, 30 m a.s.l) and NIBIO Apelsvoll (60.7°N, 10.9°E, 250 m a.s.l.) in the the northern zone, and NIBIO Landvik, Norway (58.3°N, 8.5°E, 12 m a.s.l.) and Sydsjælland GC, Denmark (55.2°N, 11.9°E, 11 m.a.s.l.) in the southern zone.

A total of 34 pure varieties (inclucing controls) and 9 seed blends/mixtures were evaluated from seeding in June 2015 until November 2018. The mowing height was 5 mm in F. rubra., Poa pratensis.

and L. perenne, and 3-4 mm in Agrostis sp., Poa trivialis and Poa annua. Fertilizers were applied at a seasonal rate of ≈10 g N m^-2 in F. rubra, A. canina and A.capillaris and 15-16 g N m^-2 in L. perenne.

A.stolonifera and Poa sp. The trials were mowed three times per week, subjected to wear from greens- type wear machines and otherwise managed according to good greenkeeping practice. The plots were evaluated in the growing season for visual turf quality, tiller density, leaf fineness, color, percent of plot area covered by undiseased turf of the seeded species, percent of plot area infected by disease

(identified if possible), Poa annua invasion (Landvik only) and daily height increment. Abiotic and biotic winter damage were assessed in spring and percent of plot area covered by moss by the end of the project. The data were analysed by ANOVA and species, varieties within species, and combinations witin three groups of seed blends/mixtures ranked, firstly for decreasing turf quality, secondly for increasing winter damage and thirdly for increasing infection of in-season disease.

The evaluation showed that the following varieties, in prioritized order, can be recommended for golf greens in the five Nordic countries, based on the criterion that they were ranked equal to or better than the control varieties:

Northern zone: Finland, central and

northern parts of Sweden, northern and continental parts of Norway, Iceland

Southern zone: Denmark, coastal regions of southern Sweden and southern Norway Festuca rubra ssp. commutata

Control variety: Musica Humboldt, Barchip None

Festuca rubra ssp. litoralis

Control variety: Cezanne None None

Agrostis capillaris

Control variety: Jorvik Heritage Rhinegold, Heritage

Agrostis stolonifera

Control variety: Independence Luminary, Riptide, Ignite Flagstick, Luminary, Riptide, Pure Distinction*

Lolium perenne

Control variety: Chardin Clementine Clementine

Poa trivialis

Control variety: Dark Horse Sabrena 1 Qasar, Sabrena 1

*Pure Distiction is susceptible to winter damage and disease and shall only be used in the climatically best areas

Poa annua ‘Two Put’ was tested but can not be recommended on Nordic golf courses. Poa pratensis tolerated mowing at 5 mm but produced rather course putting surface. It is not an alternative for greens except perhaps at northern sites with extreme winter stress.

Evaluation of seed blends of Festuca rubra ssp. commutata ‘Musica’ and F.rubra ssp. litoralis

‘Cezanne’ at weight ratios 75/25, 50/50 and 25/75 showed that the optimal ratio for pure fescue greens is 75/25 in the northern zone and 50/50 in the southern zone.

Evaluation of Lolium perenne ‘Chardin’, Poa trivialis ‘Dark Horse’ or Poa annua ‘Two Put’ as nurse

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even in the southern zone. Inclusion of P. annua cannot be recommended in any zone and inclusion of L. perenne only in the most winter-tough areas in the northern where there is no doubt that L.perenne will not survive the first winter.

Evaluation of mixtures of F.rubra and A.stolonifera or A.canina in comparison with the more

traditional mixture of F.rubra and A.capillaris at fescue and creeping bentgrass management showed F.rubra + A.stolonifera to have certain advantages such as less disease, less Poa annua invasion and less height growth. This mixture warrants further investigation on Nordic golf courses.

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1 Introduction

In-depth knowledge about turfgrass species and choice of new and improved varieties are

prerequisites for sustainable turfgrass management on golf courses. Reviews by Aamlid & Gensollen (2015) and Meyer et al (2017) documented the progress that turfgrass breeders have made and are still making, not only for aesthetic characters such as color and leaf fineness, but also for disease

resistance and abiotic stress tolerance. Surveys conducted among several hundred Nordic courses confirmed that continuus evaluation of new varieties under Nordic climate conditions is perceived as one of the most important tasks for the Scandinavian Turfgrass and Environment Research

Foundation (STERF). (Melbye 2013, 2019).

One of the suggestions from these surveys, and also from an external committee that evaluated former SCANGREEN trials, was that it should be possible to include in SCANGREEN not only new varieties, but also seed mixtures between different species and seed blends between varieties within the same turfgrass species. Based on experiences from agriculture, this suggestion is relevant as seed mixtures and blends are usually regarded to provide a more diversified plant community with greater overall resistance to diseases. While turfgrass breeding and seed companies may prefer loyal customers that purchase seed from one company only, most turfgrass managers will probably agree that the ideal solution would be to compose optimal mixtures and blends for the individual golf course by choosing species and top-ranked varieties with complementary characteristics regardless of variety owner.

Golf in the Nordic countries is played at latitudes from 55 to 70ºN and altitudes from 0 to 900 m a.s.l. Due to the variation in climatic conditions, STERF has always presented two lists of recommended varieties, one for the northern and mostly continental zone and one for the southern and mostly coastal zone (Figure 1).

These two climatic zones may also differ with regard to optimal seed blends and mixtures. Thus, in addition to the primary objective of testing new varieties of Agrostis, Festuca, Poa and Lolium for their suitability on golf course putting greens, the SCANGREEN 2015-18 test cycle also aimed at:

1. Defining the optimal ratio of slender creeping red fescue (Festuca rubra ssp. litoralis) to Chewings fescue (F. rubra ssp. commutata) in red fescue seed blends for greens in various parts of the Nordic countries. Nielsen (2010) suggested 67-75 % slender creeping red fescues and only 25-33 % Chewings fescues in blends for the Danish market, but this is probably different in more northerly areas as Chewings fescue is usually considered more winter-hardy than slender creeping red fescue.

2. Clarifying advantages and disadvantages of using fast-establishing nurse grasses such as perennial ryegrass (Lolium perenne), rough bluegrass (Poa trivialis) or even annual bluegrass (Poa annua) when seeding or reseeding creeping bentgrass (Agrostis stolonifera) greens. This question is particularly relevant on golf courses that often have to re-establish their greens at low soil temperatures in spring after winter kill.

3. Clarifying if creeping bentgrass or velvet bentgrass (Agrostis canina) can be alternative to colonial bentgrass (Agrostis capillaris) when used in mixture with red fescue on Nordic putting greens.

The combination of red fescue and velvet bentgrass was tested by Calvache et al. (2016) who found velvet bentgrass to dominate, especially at high fertilizer levels. Less is know about red fescue + creeping bentgrass mixtures, which could potentially have benefits when it comes to disease resistance and recuperative capacity. Influenced by British traditions, it is often argued that the ecological adapations of these species are too different to be compatible on greens. However, red fescue + creeping bentgrass mixtures are commonly used in Germany, and in Norway, we have sometimes seen the two species to complement each other, although at ratios varying from year to year, on golf courses trying to convert their greens from fescue to creeping bentgrass or vice versa.

An important question is if this untraditional combination of red fescue + creeping bentgrass, will be more durable and create a better putting surface when managed as fescue greens or creeping bentgrass greens ?

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2 Materials and methods

2.1 Pure species and varieties entered by plant breeders / seed companies into the project

The trials included 27 candidate varieties and seven controls representing nine different species and subspecies (Table 1). Poa pratensis was included at NIBIO’s own initiative to test the species’ tolerance to low mowing, and if it could become an alternative species for greens often exposed to winter

damage.

Seeding rates were 7, 30, 40, 15 and 25 g m^-2 for Agrostis sp., Festuca sp., Lolium perenne., Poa trivialis / Poa annua and Poa pratensis.

Table 1. Varieties in SCANGREEN 2015‐18 by species and breeding/seed companies. Varieties in bold are controls.

Agrostis stolonifera

Agrostis capillaris

Agrostis canina

F. rubra ssp.

commuta ta

F. rubra ssp.

litoralis

Poa trivialis

Poa annua

Lolium perenne

Poa prat‐

ensis

DLF

Indepen‐

dence Flagstick

Jorvik Rhinegold

Teetop Villa¹

Humboldt Wagner 1

Cezanne Aporina

Sabrena 1 Two Putt

Chardin Clemen‐

tine

Becca²

Baren‐

brug Ignite Musica

Barchip Aureline

Everris Memorial

Riptide Heritage

Germinal Borluna

Mirador

Semilas

Fito Valderrama Winter‐

way Rinovo

Svensk Jordelit

Pure Distinction Crystal Blue

PGG

Wrightson Charles

Landmark Luminary

Skånefrø Dark

Horse

Weibulls

Horto Qasar

DSV

Limou‐

sine Total

number 9³ 5 1 5 4 4 1 3 2

1: Agrostis canina ‘Villa’’ was included at Reykjavik, Apelsvoll and Sydsjælland, but not at Landvik due to space limitations

2: Poa pratensis ‘Becca’ was included as a fill‐in variety at Landvik only.

3: The number af varieties of A. stolonifera was extended to 16 in the trial at Landvik. The extra varieties were: ‘007’,

‘Declaration’, ‘Focus’, ‘MacKenzie’, ‘Tyee’, ‘Teeone’ and ‘Penncross’.

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2.2 Seed blends and mixtures added to the trials

The seed blends were composed of the control varieties (Table 2).

Firstly, we compared seed blends of Festuca rubra where the seed weight ratio of ssp. commutata to ssp. litoralis was either 75/25, 50/50 or 25/75. Our hypothesis was that the proportion of ssp.

commutata ought to be higher in the northern than in the southern test zone. These extra plots were managed as fescue greens: Mowing height 5 mm and low fertilizer inputs ( approximately 10 g N m^-2 yr^-1)

Secondly, we compared Lolium perenne and Poa trivialis as nurse grasses to speed up establishment of A. stolonifera. A central question was the persistence of the two nurse grasses and how they would affect the quality of the putting green. These extra plots were managed as creeping bentgrass greens:

Mowing height 3-4 mm and high fertilizer inputs approximately 15 g N m^-2yr^-1.

Thirdly, we studied seed mixtures of 90% F.rubra +10% A.stolonifera and 90% F.rubra +10%

A.canina as alternatives to the traditional mixture of 90% F.rubra + 10% A.capillaris. F.rubra + A.stolonifera and F.rubra + A.capillaris were studied under both fescue and creeping bentgrass management, but F.rubra + A. canina was only under fescue management as earlier trials had shown A. canina to become too dominant under creeping bentgrass management (Calvache et al. 2017).

Table 2. Seed blends and mixtures, including seeding rates (g m^‐2) of the different components

Festuca

rubra ssp.

commu‐

tata 'Musica'

Festuca rubra ssp.

litoralis

‘Cezanne'

Agrostis stolonifera

'Indep‐

endence'

Lolium perenne 'Chardin'

Poa trivialis

'Dark horse'

Poa annua

‘Two‐

Put’

Agr.

capil‐

laris

‘Jorvik’

Agr.

canina

‘Villa’

Blends of Festuca subspecies

75 % commutata, 25 % litoralis 22.5 7.5

Nurse grasses for Agrostis stolonifera

Lolium perenne 7.0 20.0

Poa trivialis 7.0 0.75

Poa annua 7.0 0.75

Agrostis sp. in mixtures with Festuca

Agrostis capillaris 13.5 13.5 3.0

Agrostis stolonifera 13.5 13.5 3.0

Agrostis canina 13.5 13.5 3.0

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2.3 Experimental sites and protocol

The trials were established on USGA-spec. greens at Reykjavik GC, Iceland (64.1°N, 21.9°W, 30 m a.s.l.), NIBIO Apelsvoll (60.7°N, 10.9°E, 250 m a.s.l.) and NIBIO Landvik (58.3°N, 8.5°E, 12 m.a.s.l.), Norway, and Sydsjælland GC, Denmark (55.2°N, 11.9°E, 11 m a.s.l.). Reykjavik and Apelsvoll were considered to represent the northern, and Landvik and Sydsjælland, the southern climatic zone of the Nordic countries (Fig. 1).

Figure 1. The four trial sites of Scangreen 2015‐18. Red line indicates the border between northern and southern zone.

Soil samples taken from the substrates at the four greens in the seeding year showed between 1 and 2

% organic matter at all sites. The soil pH and content of magnesium and calcium was higher at Sydsjælland, and especilly at Reykjavik, than at the two Norwegian sites (Table 3)

Table 3. Soil analyses of substrates at seeding.

Ignition loss, %

pH (H2O)

Plant available nutrinets in AL extracts (0.1 M NH4 lactate + 0.4 M acetic acid)

(mg (kg dry soil)^‐1)

P K Mg Ca

Reykjavik GC 1.9 8.1 <20 200 120 2600

NIBIO Apelsvoll 1.5 6.4 38 26 21 390

Sydsjælland GC 1.3 7.6 42 26 55 950

NIBIO Landvik 1.5 6.3 33 26 16 340

The trials were established according to a split-plot designs with three blocks (replicates), species on main plots and varieties on subplots. This allowed different management of the various species. Plot size was 1.0 m x 1.0 m.

The protocol has been included in Appendix 1. Most importantly, there was no use of pesticides or

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week – Monday, Wednesday and Friday. The mowing heights and annual fertilizer rates varied among speices as shown in Table 4. There were some deviations from these prescriptions, especially in conjunction with recovery after winter damage; these deviations will be described in later sections of this report.

Table 4. Mowing height and annual fertilizer rates to main plots with different species.

Mowing height low,

3 (‐4) mm

Mowing height high, (5 mm) Fertilizer rate low

≈ 10 g N m‐2 yr^‐1

Agrostis capillaris

Agrostis canina Festuca rubra Fertilizer rate high

≈ 15 g N m‐2 yr^‐1

Agrotis stolonifera Poa trivialis

Poa annua

Lolium perenne Poa pratensis

2.4 Weather conditions and implementation of protocol

The mean monthly temperatures were mostly higher than the 30 year reference (normal ) period (1961-90) at all sites (Table 5). May-July 2018 were exceptional with record-high temperature at Sydsjælland and even more so at the two Norwegian sites. Together with low rainfall, this resulted in unusually high irrigation requirements in the last evaluation year. At Landvik, the need for extra irrigation was strengthened by the need to reseed all plots after nearly 100 % winter kill caused by a

‘late winter’ with lower-than-normal temperature and snow and ice cover well into March (Photo 1)

Photo 1. Experimental green at Landvik on 20 March 2018.

Photo: Trygve S. Aamlid

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a) Reykjavik Apelsvoll Landvik Sydsjælland

2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr

Jan. 0.3 1.3 ‐0.5 ‐0.5 ‐7.7 ‐4.2 ‐4.9 ‐7.4 ‐3.4 1.7 0.9 ‐1.6 ‐0.3 0.4 2.3 ‐0.1

Feb. ‐0.8 2.8 ‐ 0.4 ‐2.8 ‐3.8 ‐6.7 ‐7.0 1.2 0.4 ‐2.0 ‐1.9 2.0 1.6 ‐1.2 0.0

Mar. 2.6 1.6 2.2 0.5 1.3 0.7 ‐5.4 ‐2.5 3.4 3.4 ‐1.2 1.0 3.3 4.5 0.1 2.5

Apr. 4.2 3.0 4.8 2.9 3.9 3.7 3.5 2.3 6.1 6.5 6.7 5.1 6.1 6.2 8.7 6.3

May 6.6 8.6 5.9 6.3 10.7 10.1 15.1 9.0 12.3 11.9 14.9 10.4 13.1 12.1 14.6 11.5

June 9.2 11.0 10.0 8.9 9.0 12.6 15.1 13.5 16.0 13.7 13.9 15.8 15.5 17.0 14.7 13.0 16 15.2 17.1 15.0 July 11.3 12.5 11.6 10.7 10.6 14.8 15.8 15.0 20.7 14.8 15.8 16.4 16.1 20.3 16.2 16.0 16.7 15.4 20.0 16.2 Aug. 11.0 11.9 10.7 ‐ 10.3 14.6 14.2 13.7 14.7 13.5 16.2 15.5 15.1 16.1 15.4 17.6 16.3 16.4 18.4 16.3 Sep. 9.2 8.6 9.5 7.0 7.4 10.8 13.6 10.3 11.1 9.1 12.9 15.1 13 12.9 11.8 13.3 16 13.2 14.5 13.3 Oct. 5.2 7.8 6.6 3.7 4.4 5.6 4.2 5.4 5.4 4.6 8.5 7.6 9.4 8.7 7.9 9.4 8.4 11.0 10.3 9.5 Nov. 1.9 3.3 ‐0.4 3.9 1.1 1.4 ‐1.2 ‐0.7 1.6 ‐1.3 5.6 2.7 3.5 5.5 3.2 7.0 3.6 5.7 5.5 5.0 Dec. ‐0.5 3.7 ‐1.3 2.3 ‐0.2 0.1 ‐0.9 ‐4.9 ‐3.4 ‐5.3 4.8 3.7 1.7 2.0 0.2 5.9 4.0 3.4 3.9 1.8

Mean ‐ 6.0 5.3 ‐ 4.4 ‐ 5.5 4.9 5.6 3.6 ‐ 8.0 8.2 8.5 6.9 ‐ 8.8 8.8 9.5 8.1

b) Reykjavik Apelsvoll Landvik Sydsjælland

2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr 2015 2016 2017 2018 30yr

Jan. 67 74 ‐ 76 46 8 60 37 149 65 221 113 41 12 75 46

Feb. 88 123 ‐ 72 18 22 31 26 85 138 143 73 47 42 11 31

Mar. 115 42 36 82 42 21 18 29 117 117 48 85 43 56 48 38

Apr. 55 176 67 58 75 33 40 32 103 66 66 58 59 41 34 38

May 24 93 150 44 66 59 23 44 97 61 40 82 11 28 16 43

June 20 47 72 89 50 39 30 58 56 60 65 110 117 76 71 55 110 54 8 49

July 35 29 57 48 52 116 59 59 27 77 106 101 99 21 92 44 106 77 14 62

Aug. 65 38 ‐ 20 62 52 109 144 59 72 185 122 125 76 113 51 93 67 122 59

Sep. 117 80 ‐ 67 67 164 21 64 85 66 322 36 291 213 136 53 52 106 17 56

Oct. 186 258 ‐ 133 86 2 39 67 46 64 72 117 346 56 162 41 72 90 39 52

Nov. 73 53 143 132 48 64 26 60

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2.4.1 Establishment and maintenance of the trials in 2015

Details from the four trials are shown in Table 6. Seed of Agrostis stolonifera ‘Valderrama’ arrived late and was therefore seeded 2-3 weeks after the the other varieties at all sites except Sydsjælland.

Turfgrass establishment was uniform in Reykjavik (Photo 2) and at Apelsvoll (Photo 3) but for unknown reason, some of the bentgrass plots established poorly and had to be reseeded twice at Landvik (Photo 4). Presumably due to inadequate irrigation, this was also the case for several plots of small-seeded species at Sydsjælland (Photo 5) Most of these problems were resolved in August and early September, and after that, all trials were assessed monthly for coverage and visual turf quality

Photo 2. Trial in Reykjavik on 30 July 2015, about six weeks after seeding. In this trial, mowing was very lenient in the seeding year.

Photo: Gudni Thorvaldsson.

Photo 3. Trial at Apelsvoll on 31 July 2015. All plots established nicely.

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Table 6. Green type seeding dates and management in the seeding year 2015.

Reykjavik Apelsvoll Landvik Sydsjælland

Type of green USGA‐spec. USGA‐spec. USGA‐spec. USGA‐spec.

Year of construction 2007 2003 2003 2006

Type of organic matter in rootzone

Soil 3‐30 cm: Composted

garden waste

0‐3 cm: Peat 4‐30 cm: Composted

garden waste

Sphagnum peat Seeding date

22 June Ca 10 July:

Valderrama

19 June 6 July: Valderrama

6‐9 June 12 June: Mirador 7 July: Valderrama

Reeseeding of problem plots: 23

July and 11 Aug.

24 June 26 Aug: Reseeding of all

Agrostis sp. + Poa trivialis + mixtures

Preplant fertilizer

Type

Everris Pre‐seeder

18‐22‐5

Grønn 8K dried chicken manure + bonbe meal

Marihøne 8‐5‐4 Plus dried chicken manure + bone meal

‐ N / P / K, g m^‐2 9.0 / 4,8 / 2.1 5.0 / 1.9 / 3.1 5.0 / 3.1 / 2.5 ‐

Plots covered by tarp after seeding / days

Yes/11 days No Yes / 12 days

Yes (plots covered both after seeding and

reseeding )

Ferti‐

lization after seeding

Fertilizer type(s)

Everris 18‐22‐05, Everris 19‐19‐5, Angus 12‐3‐9 and

6‐5‐11

Andersson 13‐2‐13 Arena Golf NK 13‐15 Scotts Zero Phosphate

14‐0‐10

Andersson 13‐2‐13 Greenmaster 14‐0‐10

Wallco 5‐1‐4

G‐Boost 20‐0‐4, G‐Beast 6‐6‐6, G Kalimax 21‐0‐17 +Bionutria Ca + micro First application after seeding 30 June 6 July 25 June Ca 20 July Last application before winter

29 Sept. 28 Sept. 27 Oct. Last N: Wk 41. Last: K,

Mg, S and Micro: wk 48

Number of applications 16 9 13 9

Total rate of N, P and K, to A.stolonifera, Poa sp., L.perenne, and high input mixtures, g m^‐2

9.6/4.5/7 25 / 6 / 17

29 / 6 / 21¹+ 12 / 5 / 7 (on plots

reseeded many times)

8.2 / 2.1 / 10.9 + preplant Samme rate to all

species Total rate of N, P and K, to F.

rubra, A.capillaris, A.canina, and low input mixtures g m^‐2

6,7‐3,2‐4,9 17 / 5 / 11 20 / 5 / 14

Mowing

Type of mower

Walk‐behind Walk – behind Walk – behind

Rotary mower in Aug.

before reseeding.

Sep‐ Oct: Triplex First mowing after seeding

3 July 16 July 24 June 10 Aug (Only fescue

and Lolium plots)

Height of cut at first mowing 15 mm 9 mm 11 mm ‐

Lowest height in Agrostis sp.,

Poa annua and Poa trivialis 7 mm 4 mm 4.5 mm ‐

Lowest height in

Festuca/Lolium/Poa pratensis 7 mm 6 mm 6 mm ‐

Last mowing before

winter / height 29 Sept.: /7mm 12 Oct.: 4 / 6 mm 2 Nov.: 4.5 / 6 mm ‐

Top‐

dressing

Type of sand Pure sand, grain size 0‐1 mm

Pure sand, grain size 0.2 – 0.7 mm

Pure sand, grain size

0.2 – 0.7mm ‐

Number of applications 4 4 13 ‐

Total height 4‐5 mm 1.7 mm 2.8 mm ‐

Verticutting, aeration None None None None

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Photo 4. SCANGREEN trial at Landvik on 31 July. A few plots of Agrostis have been reseeded and are covered by white, permeable tarp.

Photo: Trygve S. Aamlid.

Photo 5. Seeding the SCANGREEN trial at Sydsjælland GK on 25 June 2015.

Photo: Anne Mette Dahl Jensen.

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Photo 6. : SCANGREEN trial at Sydsjælland on 31 July 2015. Plots of Agrostis sp. and Poa trivialis had established poorly due to inadequate irrigation / poor seed-soil contact and therefore had to be

reseeded in August.

Photo: Anne Mette Dahl Jensen.

Photo 7. SCANGREEN trial in Reykjavik on 24 Sept. 2015. Establishment was better than in earlier SCANGREEN trials on Iceland.

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2.4.2 Winter 2015‐16 and management in 2016

The ice cover in winter 2015-16 was long in Reykjavik and at Apelsvoll. Lolium sp. and Poa annua had to be reseeded in Reykjavik (Photo 8). Due to the reseeding and a following dry period in July, the trial received a lot of irrigation this year.

At Apelsvoll all species were reseeded in the beginning of June (Photo 9). At Landvik and Sydsjælland there were few winterdamages and no need for reseeding. At Landvik Poa annua ‘Two Put’ had severe injuries from microdochim patch (Photo 10), but it recovered without reseeding.

Management of the four trials in 2016 was mostly according to the protocol except that wear treatements were not conducted after reseeding at Apelsvoll (Table 7).

Photo 8. SCANGREEN trial in Reykjavik on 12 June 2016. Plots with Lolium perenne (back row) and Poa annua (three plots in central row) ) had to be reseeded.

Photo 9. Reseeding all plots at Apelsvoll on 1-3 June 2016.

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Table 7. Winter weather 2015‐16 and green management of in 2016.

Reykjavik Apelsvoll Landvik Sydsjælland

Snow cover during winter

Duration of snow or ice

cover 61 days Snow: 90 days

Ice: 60 days

6 periods with snow

56 days in total 9 days

Soil frozen under snow or

ice 49 days From 25 Dec to 10

Apr.

Frozen only 21 days

(mainly March) 9 days Re‐seeding Species that had to be

reseeded

Lolium perenne Poa annua

All species None None

Reseeding, date June 23 1‐3 June -

Ferti‐

lization

Fertilizer type(s)

N‐xt 9‐5.5 Ammonium‐sulfate

Potassium‐nitrate Angus 12‐3‐9

Iron sulfate

Arena Start 15‐5‐7 Arena Fairway 15‐3‐8

Scotts 12‐0‐9 Fe Arena Golf 13‐0‐15

Wallco 5‐1‐4 (liquid) Greenmaster 14‐0‐10 (granular) Andersson 13‐2‐13

(granular), Mn‐sulfate

G Boost 20‐0‐4 G Beast 6‐6‐6 G Kalimax 21‐0‐

17 Mg‐sulfate Mn‐sulfate

Cu sulfate First application in spring About 10 June 15 June (2 weeks

(after reseeding) 6 April 4. April Last application before

winter About 1 Oct. 7. Oct. 1 Nov. 23 Oct.

Total rate of N, P and K, to A.stolonifera and Poa spp., kg /100 m²

12.5 / 1.5 / 9.8 24.5 / 3.3 / 16.3 15.8 / 1.8 / 12.4

25.9 / 2.3 / 23.8

Total rate of N, P and K, to A.capillaris, A.canina and F.rubra, g m^‐2

7.8 / 0.9 / 6.1 16.5 / 2.3 / 1.08 10.3 / 1.2 / 8.1

13.0/1.2/11.9

Mowing

Type of mower Walk‐behind Walk‐behind Walk‐behind Triplex

First in spring:

Date / height 25 April / 5 mm. 14 June 8 April / 6.5 mm all

species 6 mm

Lowest height in Agrostis

sp. / P. tivialis / P.annua 4 mm 4 mm 3 mm 4.2 mm

Lowest height in Festuca

/Lolium/Poa pratensis 5 mm 6 mm 5 mm 5 mm

Last before winter:

Date / height 7 Oct. 7 Oct., 4mm /

7 mm

28 Oct, 3 mm / 7 mm

3. Nov./ 6 mm Irrigation

Number of times 93 (due to reseeding)

35 30 6

Total quantity 372 mm 300 mm 460 mm ‐

Top‐

dressing

Type of sand Pure sand Pure sand Pure sand Green Mix light

(0.8 % OM)

Total height ‐ 3 mm 7.5 mm ‐

Veriti‐

cutting

No of times, Agrostis 4 0 0 0

No of times, other species

2 0 0 0

Slicing, 5 cm

depth No of times, Agrostis 0 2 8 0

0 2 8 0

Spiking, 6

mm tines No of times, Agrostis 5 0 4 5

5 0 4 0

Deep aeration

Date ‐ 2. Nov ‐ Dot machine

Equipment, depth ‐ Digging fork, 10 cm ‐ 16 cm

Rolling with wear machine

Number of passes

35 (11700 rounds of

golf)

0

63 (21000 rounds of

golf)

32 (16700 rounds of

golf)

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Photo 10.: Four species in SCANGREEN trial at Landvik on 6 May 2016. The only variety with severe winter injury (caused by microdochium patch) was Poa annua ‘Two Put’.

Photo: Trygve S. Aamlid.

2.4.3 Winter 2016‐17 and management in 2017

The duration of snow in Reykjavik and at Apelsvoll during the winter 2016-17 was not as long as the year before (Table 8). No species had to be reseeded in Reykjavik. At Apelvoll there was long-lasting ice cover (Photo 11), but it was crushed three times in January and February and never became very compact. In March we also spread granules of LECA to melt the ice at Apelsvoll (Photo 12). Despite this, all varieties of Lolium sp., Poa trivialis and Poa annua, as well as A. stolonifera ‘Pure

Distinction’ and Agrostis capillaris ‘Charles’ were dead and had to be reseeded in the beginning of June (Photo 13).

The second winter at Landvik was mild, and there was only some snow mold damage (Photo 14) . At Sydsjælland there were few winter damages and no need for reseeding, but the plots with Poa trivialis did not thrive and produced a dark purple color (Photo 15).

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Table 8. Winter‐weather 2016‐17 and green management in 2017.

Korpa Apelsvoll Landvik Sydsjælland

Snow cover during winter

Duration of snow or ice

cover 40 days Snow:Feb‐Mar.

Ice:1 Dec‐15 Mar.

16 days in Feb. +

10 days in March 11 days (snow) Soil frozen Only a few days 1 Dec‐15 Mar 16 days in Feb. 11 days Re‐seeding Species / varieties / seed

mixtures that had to be reseeded

None

Poa trivialis (all) Lolium perenne (all)

Pa: ‘Two Put’, Ast:

‘Pure Distiction’, Acap: ‘Charles’

Mixture: Pa + Ast

None None

Reseeding, date ‐ 1 June ‐ ‐

Fertilization

Fertilizer type(s) PionerGreen 18‐2‐15 Ammonium‐sulfate

Potassium‐nitrate Angus 12‐3‐9

Iron sulfate

Arena Høst Extra, Greenmaster 14‐0‐

10, Arena Golf N, Proturf 12‐5‐20

Proturf 18‐0‐7

Wallco 5‐1‐5 (liquid) Greenmaster

Cold Start Greenmaster 14‐

0‐10 (granular)

G Boost 20‐0‐4 G Beast 6‐6‐6

G Kalimax 21‐0‐17 Mg‐sulfate Mn‐sulfate Cu‐ sulfate

First application in spring 3 May 19 May 5 April 3 April

Last application

before winter 6 Oct. 1 Oct. 31 Oct. 18 Nov.

Total rate of N, P and K, to A.stolonifera and Poa spp., g m^‐2

15.4 / 1.9 / 11.5 15.4 / 2.4 / 18.7 14.6 / 1.63/ 9.93 30.4 / 3.4 / 26.0 Total rate of N, P and K,

to A.capillaris, A.canina and F.rubra, kg /100 m²

9.6 / 1.2 / 7.2 10.0 / 1.6 / 12.2 9.5 / 1.1 / 6.5 17.5 / 2.3 / 14.1

Mowing

Type of mower Walk Behind Walk behind Walk behind Triplex

First in spring:

Date, height 3 May, 6 mm 19 May, 6mm 3 April , 5 / 7 mm 4 April, 6 mm Lowest height in Agrostis

sp., P. annua, P. trivialis 4 mm 4 mm 3 mm 4.2 mm

Lowest height in

Festuca/Lolium/P.pratnsis 5mm 6 mm 5 mm 5 mm

Last before winter:

Date / height 19 Oct. 18 Oct., 4 / 6mm 3.Nov., 3 / 7 mm 16 Nov./ 6 mm

Irrigation Number of times 36 60 23 6

Total quantity, mm 176 mm 600 mm 450 mm ‐

Top‐dressing Type of sand Pure Sand Pure sand 0.3‐0.5 mm Green Mix

light, 0.8 % OM

Total quantity 8 mm ‐ 7,75 mm ‐

Veritcal mowing

No of times, other

species 2 0 0 0

Slicing, 5 cm depth

No of times, other

species 0 0 10 0

Spiking, 6 mm tines

2 1 0

Deep aeration,

Date 24 okt ‐ Dot machine

Equipment, depth 20cm ‐ 16 cm

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Photo 11. SCANGREEN trial at Apelsvoll on 3 January 2017. The ice was 2-5 cm thick but porous.

Photo: Pia Heltoft.

Photo 12. SCANGREEN trial at Apelsvoll on 3 April 2017, shortly after snow and ice melt. First row comprises Poa pratensis ‘Limousine’ (green) and three varieties of Lolium perenne (all dead). Black

granules (LECA) had been spread to melt the ice.

Photo: Pia Heltoft.

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Photo 13. Photo taken from a drone over the SCANGREEN trial at Apelsvoll on 4 May 2017.

Photo: Maximilian Pircher

Photo 14. SCANGREEN trial at Landvik on 23 March 2017: Some snow mold, but no severe winter damage.

Photo: Trygve S. Aamlid

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Photo 15: SCANGREEN trial at Sydsjælland in June 2017. Nearest row with brown plots are Poa trivialis.

Photo: Per Sørensen.

Photo 16. SCANGREEN trial at Korpa GC, Reykjavik, on 10 Oct. 2017.

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2.4.4 Winter 2017‐18 and management in 2018

The winter 2017-18 resulted in severe damages due to ice and melting water at Landvik. The damages were worse than at Apelsvoll, and all plots had to be reseeded in spring (Photos 17-21). For that reason and due to the dry summer the irrigation at Landvik in 2018 was twice as high as the preceding years (Table 9).

At Apelsvoll the snow was removed until mid January (Photo 22). The winter was more stable than at

Landvik, and reeeding was limited to the same species, varieties and seed blends as the year before (Photo 23).

Photo 17. Landvik, 7 January 2018. High winter precipitation and fluctuating temperature resulted in ice and water damage.

Photo: Trygve S Aamlid

Photo 18. Ice-encased SCANGREEN-trial at Landvik, early March 2018. The snow had been removed